SqlServerPermission: Add missing server permissions

Details of the scenario you tried and the problem that is occurring

It should be possible to add any server permissions, not just the current four. Specifically, it would help to add the permissions 'VIEW ANY DATABASE' and 'VIEW ANY DEFINITION', which are required to configure an SCOM SQL MP monitor account (https://blogs.msdn.microsoft.com/tysonpaul/2016/04/09/sql-run-as-account-configuration-for-scom-made-easy/)

The DSC configuration that is using the resource (as detailed as possible)

N/A

Version of the operating system and PowerShell the target node is running

Windows Server 2016, inbox powershell

SQL Server edition and version the target node is running

Edition : Standard Edition
Version : 13.1.4001.0
Language : 1033

What SQL Server PowerShell modules, and which version, are present on the target node.

xSQLServer 9.1.0.0 C:\Program Files\WindowsPowerShell\Modules\xSQLServer\9.1.0.0\xSQLServer.psd1
xSQLServer 9.0.0.0 C:\Program Files\WindowsPowerShell\Modules\xSQLServer\9.0.0.0\xSQLServer.psd1
SQLPS 1.0 C:\Program Files (x86)\Microsoft SQL Server\130\Tools\PowerShell\Modules\SQLPS\SQLPS.psd1

Version of the DSC module you're using, or write 'dev' if you're using current dev branch

SqlServerDsc 11.1.0.0 C:\Program Files\WindowsPowerShell\Modules\SqlServerDsc\11.1.0.0\SqlServerDsc.psd1

Start at the SqlServerPermission resource and review how its current four server permissions are represented and validated. Extend the resource to support the requested VIEW ANY DATABASE and VIEW ANY DEFINITION permissions, then verify that server permissions are no longer limited to the existing four.